Biological and chemical reactions on molecules (e.g. DNA or proteins) and on cells for analysis or diagnosis are most of the time carried out in (stagnant or flowing) liquids. Under atmospheric conditions liquids generally contain dissolved gases (e.g. O2, N2, CO2). That is why so-called gas bubbles are formed in stagnant liquids. These gas bubbles complicate the analyses and might distort the corresponding results. If a specific reaction, in particular, is to be detected on a carrier wall, such a reaction may be complicated by gas bubbles. Hence, when gas-impermeable sample carriers are used, the liquids must be degasified to prevent the occurrence of gas bubbles.
Especially in microfluid systems which comprise channels in a carrier, gas bubbles may moreover cause clogging or changes in fluidics.
On the other hand, if a sample chamber or a sample carrier consists of a material that can absorb gases, gases absorbed from the environment, for example air, can diffuse during an analysis in an uncontrolled manner into the liquid. This also causes the development of gas bubbles in already degasified liquids. This problem will particularly arise upon changes in temperature of the liquids or sample chambers. When the temperature is increased, the gas solubility in solids and above all in liquids is reduced. Since a one-hundred-percent degasification is hardly possible, it is highly probable that upon an increase in temperature bubbles will also be formed in liquids that have already been “degasified” once.
For example, if a PCR (polymerase chain reaction) is carried out at temperature cycles of 90° C. in a sample chamber of plastic having a high gas capacity, possibly existing gases may pass in conventional methods from a non-degasified plastic in an uncontrolled manner into the sample chamber.